Oiling system for rock drills



Jan. 15, 1952 j F S 2,582,689

OILING SYSTEM FOR ROCK DRILLS Filed Aug. 18, 1947 BNVENTOR f HENRY O. FosSuM ATTORNEY I Patented Jan. 15, 1 952 .humreo PATENT orrlce Henry 0. Fossum, Detroit, Mich., assignor to Chicago Pneumatic lool Company. New York,

N. Y., a corporation of New Jersey Application August 18, 1947, Serial No. 769,176

This invention relates to lubricating apparatus for fluid actuated tools such as rock drills. In rock drills, especially. of the sinker typeythe use. of a, line oiler is not expedient, and consequently it is conventional to provide a reservoir within the body of the tool to carry a limited supply of oil for distribution to the working parts by entrainment in the stream of live air which actuates the hammer :piston. Theoil is conducted through a system of portings, from the reservoir to a point, adjacent the stream of. live air; but, in drills of the class wherein the reservoir is remotely located from the point through which the live air is admitted into, the

oil system, it is ,well known inthe art that there;

will be norsubstantial amountiof oil conveyed from the reservoir into the live air-stream during the normal operation of the drill. During such operation, however, the pulsations in the live air stream incident to the alternate admis-. sion and cut-off of the live air supplied to reciprocate the hammer piston, create .an oil,

Regulating orifices are customarily provided inthe portings of the lubricating system to prevent premature dissipation and consequent waste of the lubricant; and since theorifices are nec-J essarily of restricted cross-section, clogging. fre-,

quently occurs with theresult that the'tool is not lubricated even though the reservoir is well supplied. In order to remove theclogging detritus, a wire is. ordinarily inserted through the restricted orifices; but since the orifices are not accessibles from the outside of the tool, the tool'has to be dismantled. Obviously, this is inconvenient and results in the loss of time.v Furthermore,

when the tool is operated in clogged condition.

there is the likelihood of damage to the tool because of lack of lubrication. It is another object of the invention to provide means of preventing the clogging of the lubricating system.

It is a further object of the invention to provide a device arranged in an oiling system which includes a plunger fitting loosely into a sleeve disposed within the portings to act as a check the working parts or the tool upon the sudden drop of pressure incident to cutting off the supply of live air to the tool.

Another object of the invention is to provide such a device to limit to predetermined amounts the supplyof oil which will advance into the tool at each cutting off of the live air supply.

Still another object isto provide means to prevent the accumulation of detritus in the lubricating system.

-Other, objects and features will appear more closely from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is a longitudinal section of a fragmentary portion of a rock drill embodying the invention, with the piston being illustrated, at the start of its return stroke and the distributing valve being shown on the right half, of the illustration in rear position, and on the left half of the illustration in forward position;

Fig. 2 is a cross section, taken on line 2-2 of Fig. l, of the pawl and ratchet mechanism arranged in relation to the terminal port of the lubricating system of the invention; and

Fig. 3 is a longitudinal section, on a larger scale than Fig. 1, of the sleeve and plunger arranged in open position to permit the movement of the oil within the lubricating system.

Referring more particularly to the drawing, the invention is shown embodied in a pressure fluid operated rock drill of the type disclosed in applicants U, S. Patent 2,448,875, dated September 7, 1948. Such a rock drill comprises a" cylinder l 0 having achamber l I therein in which a hammer piston l2 reciprocates. The drill is provided with conventional rotation mechanism for imparting intermittent rotary movement of the piston, such mechanism comprising a rifle nut (not shown) screwed into a complementary threaded recess in the rear face of the piston, a rifle bar I 3 having helical splines I4 slidably engaging the rifle nut, a head I5 (Fig. 2) on the rifle bar, a series of pawls I6 carried on the head, and a ratchet ring I! surrounding the head and pawls. The ratchet ring is stationary and is supported by the cylinder" I0 and by a back head [8, the latter being rigidly secured to the cylinder by conventional means. Back head I8 completes the rear end closure of the cylinder I0, and washer I9 provides a closure for the front end of the cylinder.

Cylinder II] has a counterbore 2| within which is arranged a valve chest, generally indicated at 26 which has locatinsxflanges 21! and 28 arranged to maintain the bushing against axial movement within the valve chest. Such bushing forms a bearing for the rotating rifle bar I 3.

Surrounding the bushing 26 is an annular dis tributing valve 29 which is mounted for limited Within the valve chest 22 is mounted a bushing axial reciprocation to direct live air' alternately T into the front piston chamber 3| and rear piston chamber 32 to reciprocate the piston. Such valve may be any of several types well known in the art; The valve illustrated has been found eflective in a rock drill of the type shown in which live air from a source ofsupply (not shown) is shown in open or Working position andlive an:

enters therethrough to passage 34, reservoir 35, and the interior ratchet r ingfl F-'ig, 2i to front reservoir 36, thence-through ports 31 to the interior-offl valve 29 and: out through radially arranged-ports 38 to rear piston-chamber 32,. driv ing piston-I 2 on-i-ts forward stroke During thev iorward stroke of the piston, valve: 29 is held in its rearward position- (shown on the-right in-Fig. 1) by pressure of the live air oniorwardface 39. as the air advances through ports up When piston 2-- on its-forward stroke uncovers kicker port c 'iiveau is admlitted by way of blower-valve 42, slot 43, and port 44 to impinge against-the rear face 45 of di'stri-butingvaI-ve flange, thereby to-tr-ip the valve'forward to shut off the live.

air from the rear chamber 32 Upon the completion of the; forward strokeof the piston, asshown in Fig'. 1, rear piston chamber 32 is evacu ated through the main exhaust'port 4 in valve The piston is now inposition-tebe driven rearwardly by the admissionof live air through annular passage 48-; annular recess formed}. on the rear portion of the valveannular grooveil, passageway 52 (diagrammatically represented in Fig; 1 into the front pistonchamber it where it wilIimp-inge against the front face-53 of pistonl2. 'I'hevalve29, during the first portion of the rearward travel of" the piston, is held" initsfor ward position by the pressure of the live air on its rear face 5'4. As piston- F2 travl'srearWard ly it closes exhaust port 55; Pressure of -theresidiaalair in the rear chamber 32 will. then-be builtup until, at a predetermined-position of the piston, it will be sufficiently high on face--39 i the valve to overcome the forward pressure on face 54- and to trip the valve to rearward position;

thus completing the cycle. While the valve is-in forward position, there is, in additior'i-to thedif ferential pressurejustdescribed, a constant pres sure against face 56 exerted by; the live airwithin thevaive which exceeds-the pressure on face 51; andathis'v differential also in trippmg of thewalvein the: rearward direction. The last described, differential,v itshould-beobserved, does;

IIOKGXiStZWhSILIhQ valve is in rear position. In,

that'case, the live air moving orward-athigh; speed-will; exert a higher pressure on. the; facev 51 thanon face. 561 even though; itsv area is the-.smaflen; The piston. its rearymrdv travel: also closes: kicker port 4|, further communication between the valve chamber andthe rising pressurein the 7 er port 54a (not shown but diagrammatically represented in Fig. 1 permits the escape to atmosphere of the entrapped air in the portion of the valve chamber exterior to the valve thereby to assist in the rearward shifting of the valve.

Turning now to the oil lubricating system, reservoir BI is provided at the front end of the cyl inder; by the mating of annular recess 62' in the cylinder) and annular-recess 63* in the washer l9, Oil is supplied thereto by the operator from time to time, as required, through the aperture which is threaded for the reception of filler plug 65. Adjacent to the reservoir and in the interiorface of the cylinder are two longitudinally extending g-rooves or slots 66 and 61 formed on diametrically opposed portions of the chamber. Such groovesor, slots are connected by an annular groove 68, and by means of ports 69 they establish communication between the reservoir 6| and longitudinal passage II in the cylinder It. At its rear end, passage- I E: is. connected'by a port 12 (Fig. 3'1 to thean-nular recess l3: imthe avalve;

block- 24;- encompassing sleeve 14. Such sleeve-is arranged within a. limited bore 15in the valve block 24 and; is, formed with-alongitudinat bore Win rear portiomandacounter'boi'e T1 forward. portion. Port lei-connects the-annularl recess l3 to the counterbore FH-andbymeansofi bore W -communication is established betweencounterbore -T'l and the longitudinali passage it extendmgthrough the valve block 24' and ratchet ring Iii-in ofisetrelation tothelongitudinalpassage-1| Passage Ht 'leadsqear-wardly through the ratchet ring H to the inwardly inclined port:

&|'. :whichterminates in a restricted aperture- 82 I bore H and is ofif'somewhat shorter length then the length ofthe counterbore. The-diaaneter'of" the: main body' as name p mger issiignny less than the diameter of thecounterbore 1 -1, and

the plunger extension 86,-w'hiehprojects into the 7 here m is or; slightly less diameter than that of saidijborel The plunger is-thus loosely supportedthe sleeve andiis free for limited movement: in relation ta the enclosing-structure"ofatheitcolcon siderect asv a wit; In operation, as the entire tool: vibratesrlong i'tudinally in: response to the im-- pacts thiezhammer: piston, the plunger byitsawnsinertiay remamsnbstantiallystationary i the. longitudinalr; permitted by the; counterbore As; the; entire tool jumps forwardlyv when the hammer pistonstrikes: the front head v air; cushion or the drill steel (not; shown);

as the; case may plungeisfwil-li retrial-m star tinniary; until; its: tapered portion: 81 is strickerr' by the correspondinglyztapereds seal-128:8 formed." betweemthe bore 16. and; counterboreni ,When: the. entire tool: viwrnhsrearwanily: a the hammerpistontreversesiand meets theaircush-ion inrearchamber 32;,the plung twill: again; remain sta by: m rtiaunt encoun er d ythawaik Basti valve enzii whieh erves'as a forward.

cylinder chamber-being thereby cut off. Arbleem Rt closure thecounterbore; 11;; Suchr alternate:

impacts of the plunger against seat 88 and the wall 89 cause the plunger to disintegrate any small particles of foreign matter that may have become introduced into the oil in which the plunger is submersed and which may hang up or stick in this restricted zone.

Whenever the operator shuts off the supply of live air and the pressure of the live air within the body of the tool drops, the oil or oil foam in the lubricating system will rush toward the zone of low pressure. This sudden movement of the oil will force the plunger 84 rearwardly so that the tapered portion 81 will seat at 88 and cut off further flow of the oil toward the outlet aperture 82. Obviously, only a limited amount of oil will have passed from the counterbore H to the bore 18 by the time the valve seats.

The length and diameters of the plunger may be varied to provide for the different viscosities of oil. Obviously, if a rod of smaller diameters is provided, the space between the bores of the sleeve and the diameters of the rod will increase and the oil will pass more freely therethrough. With oils of greater viscosity, the substitution of a plunger of smaller diameters has been found advantageous. A similar effect is produced by the use of a shorter rod. The space taken up by the rod, and accordingly the resistance to the passage of oil through the sleeve bores, is diminished and an oil of greater viscosity is more free to pass therethrough.

It is to be understood that although a single embodiment of the invention has been shown in the drawin and described in the specification, the invention is not limited to such embodiment but is capable of modification and substitution of parts and general reorganization within the scope of the appended claims.

What is claimed is:

1. In a percussive tool of the class wherein a hammer piston, reciprocated by live air from a conducting passage, imparts longitudinal jars to theentire tool as a unit, a lubricating system comprising a reservoir, an oil transmission passage leading from the reservoir to a point adjacent the live air conducting passage within the tool and connecting with said passage, a sleeve in the transmission passage having a bore, a counterbore, and a tapered connectingportion, said transmission passage intersecting the sleeve at the side thereof in the region of the counterbore, a cylindrical plunger arranged within the sleeve having a main body, an extension thereto, anda tapered connecting portion, said main body and extension being arranged within the counterbore and bore of the sleeve respectively in a manner to provide a continuous clearance space between the periphery of the plunger and the sleeve for the passage of oil about the plunger, the tapered portion of the plunger being adapted to seat upon the tapered portion of the sleeve, the plunger being adapted to remain immovable by inertia in relation to the entire tool thereby to reciprocate in the oil in the transmission passage to prevent the accumulation of foreign matter therein, said plunger being further adapted to seat upon the tapered portion of the sleeve to act as a check valve to prevent the flow of oil toward the live air conducting passage upon the sudden drop in air pressure incident to shutting off the supply to live air to the tool.

2. In a percussive tool of the class wherein the motor is actuated by pressure fluid from a conducting passage, a lubricating system comprisin a supply reservoir, enclosed oil transmission means leading from the reservoir to a point adjacent to the pressure fluid conducting passage within the tool, a sleeve in the transmission means having a tapered portion adapted to serve as a valve seat, said transmission means including a passageway which at one point intersects the sleeve at the side thereof, and a cylindrical plunger in the sleeve having a tapered portion to cooperate with the valve seat, the plunger being mounted in the sleeve in a manner to provide a continuous clearance space between the periphery of the plunger and the sleeve for the passage of oil about the plunger when the plunger is not in a seated position, said plunger being adapted in response to the sudden drop of pressure incident to the shutting off of the supply of pressure fluid to the motor, to act as a check valve to prevent the further passage of oil from the reservoir to the pressure fluid conducting passage.

HENRY O. FOSSUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,405,375 Allen Jan. 31', 1922 1,557,675 Eichelberger Oct. 20, 1925 1,558,221 Bayles et a1. Oct. 20, 1925 1,700,419 Penberthy Jan. 29, 1929 1,789,117 Smith Jan. 13, 1931 1,815,111 Mercer July 21, 1931 1,864,536 Hamerly June 28, 1932 1,926,158 Macomber Sept. 12, 1933 

